The present invention relates generally to vehicle communication systems, and more particularly, to a method and apparatus for communicating between multiple vehicles in a close proximity of each other.
Collision countermeasure and warning systems are becoming more widely used. Collision countermeasure and warning systems detect objects or vehicles within close proximity of a host vehicle and perform safety operations so as to prevent or minimize the likelihood of a collision and any resulting injury to an occupant.
In the development of collision countermeasure and warning systems vehicle-to-vehicle communications has been suggested for increased host vehicle awareness of other vehicles or potentially hazardous conditions that may exist within a close proximity to the host vehicle.
Vehicle-to-vehicle communication for safety purposes requires several distinct types of data communication. A host vehicle should be aware of vehicles that may be approaching from multiple directions and at various velocities. A host vehicle should also be aware of various traffic conditions, such as a slow moving congested traffic situation versus a clear faster moving situation when a first vehicle may pass a second vehicle. Thus, a host vehicle in motion must be able to discover and communicate with additional vehicles that are traveling in a concurrent manner, including vehicles approaching from a forward, rearward, or lateral direction of a host vehicle.
Traditional vehicle communication systems have a vehicle time delay discovery problem. The faster the vehicles are moving the more significant the time delay becomes. Traditional vehicle communication systems operate sufficiently in discovering vehicles in a close proximity under slow moving traffic conditions. Generally, during a slow moving traffic condition vehicles tend to remain in host vehicle range for a reasonable amount of time, allowing the host vehicle to discover the vehicles without any timing issues. The timing issues become more evident when a vehicle is approaching in a lateral direction, and are a particular concern for vehicles approaching from the forward or rearward directions. Vehicles approaching from the forward or rearward directions, such as during a passing situation, must be discovered at a relatively large distance from the host vehicle. Large time delays must be overcome in discovery of a passing vehicle as compared with time that is actually required to pass a vehicle, which is short.
The lateral approaching vehicle situation introduces an additional problem with existing vehicle communication systems. Objects between the host vehicle and the approaching vehicle may block communication signals and make detecting laterally approaching vehicles difficult. Thus, network communication is crucial to provide advanced warning of objects or potential hazards to vehicles within the network.
Ad hoc wireless mobile networks are commonly used because of their associated desirable benefits for vehicle-to-vehicle data communication including: lack of reliance on third party infrastructures, ability to adapt to local conditions readily, ability to allocate resources on a local level, and absence of single points of failure. Also, commodity implementations of ad hoc networking hardware are readily available and well proven. However, ad hoc wireless mobile networks have disadvantages associated with routing of communication signals.
Traditional networks differ from wireless mobile networks in that the network devices are connected in contained network spaces in which each device has equal access to the other devices, and communicate through a single network device to access another network space. Furthermore, in traditional networks, the addressing of individual devices is abstracted from the geographical relationship between devices. Ad hoc wireless mobile network devices, however, do not have contained network spaces or equal access to other devices. Additionally, connection between devices is very location dependent because wireless network devices have finite range.
Vehicle-to-vehicle network devices are constantly moving in and out of range and topology of the network is constantly changing. The density of the network is also constantly changing. Therefore, traditional dynamic network routing concepts, in which devices are discovered on the network and routes between devices are calculated and stored, are difficult to apply.
Referring now to FIG. 1, a vehicle communication signal pattern diagram 10 for multiple vehicles 12 in a tight cluster situation using ad hoc vehicle communication and omni-directional antennas, is shown. Arbitration is easily handled between the omni-directional antennas using collision detection and recovery or time domain multiplexing approaches. Each vehicle is able to communicate with every other vehicle in the tight cluster due to overlapping of each vehicle transmission range 14.
Referring now to FIG. 2, a vehicle communication signal pattern diagram 16 for multiple vehicles 18 in a spread out cluster situation using ad hoc vehicle communication and omni-directional antennas, is shown. When a cluster of vehicles 20 is spread out enough that not all vehicles are in communication range of each other, then handshaking mechanisms are required. The handshaking mechanisms can become congested. As an illustrative example, vehicle A may transmit a request to send (RTS) to vehicle B, vehicle B then responds with a clear to send (CTS) to vehicle A. Since vehicle C is in range of vehicle B, vehicle C must wait to respond to a RTS from vehicle D so as not to conflict with vehicle Axe2x80x3s transmission to vehicle B. Vehicle E sends a RTS to vehicle D, but vehicle D is waiting for vehicle Cxe2x80x3s CTS and vehicle C is waiting for vehicle A and vehicle B to finish communicating. The handshaking methods are less efficient than collision detection approaches, as in the tight cluster situation, and can lead to network gridlock under certain conditions.
It would therefore be desirable to develop a wireless mobile communication network for vehicle-to-vehicle communication that is feasible to implement for various approaching vehicle situations, that overcomes the above mentioned timing issues, and that is cost effective.
The present invention provides a method and apparatus for communicating between multiple vehicles in close proximity to each other. An inter-vehicle wireless communication and warning system for a host vehicle within a wireless communication network is provided. The system includes a first variable antenna that receives a vehicle discovery signal and a variable amplifier that is electrically coupled to the first variable antenna, which modifies the vehicle discovery signal. A smart transmission antenna focuses and transmits a pattern signal to at least another vehicle in the wireless communication network. A smart antenna amplifier is electrically coupled to the smart antenna and modifies the pattern signal. A main controller is electrically coupled to the variable amplifier, the smart antenna amplifier, and a vehicle network. The main controller generates the pattern signal in response to the vehicle discovery signal and a vehicle network signal.
One of several advantages of the present invention is the incorporation of smart antennas and smart antenna control into an inter-vehicle communication system. In so doing, a vehicle-communication pattern may be adjusted to meet a particular communication requirement. Additionally, the smart antennas allow for quick switching between patterns.
Another advantage of the present invention is the synchronization of a global clock signal and vehicle communication patterns, thereby, minimizing interference between neighboring transceivers and allowing concurrent vehicle communication involving several patterns that are not interfering with each other.
Furthermore, the present invention utilizes multiple vehicle technologies that are widely available to minimize additional costs to a vehicle system.
Other advantages and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.